Why are the biographical works of Shri Mahipati and Shri Dasganu Maharaj considered unsuitable for a detailed Saptah of a single saint?

The preface in Chapter 0 explains that while one can perform a Parayan or Saptah of the collective works by Shri Mahipati and Shri Dasganu Maharaj, these books are not ideal for focusing on a single saint's life. The reason provided is that the biographies within their great works—such as Shri Bhaktalilamrut—are not comprehensive or detailed. Often, a specific saint's biography might only occupy two or three pages, which is insufficient for a dedicated, in-depth Parayan or Saptah focused solely on that one individual.